This application relates to a variable block shaft for use in a hydraulic unit for an integrated drive generator.
Integrated drive generators are known and often utilized in aircraft. As known, a gas turbine engine on the aircraft provides a drive input into a generator input shaft. The generator typically includes a disconnect shaft that can transmit the input into a gear differential. The gear differential selectively drives a main generator to provide electric power for various uses on the aircraft.
It is desirable that the generated power be of a desired constant frequency. However, the speed from the input shaft will vary during operation of the gas turbine engine. This would result in variable frequency.
Integrated drive generators are provided with speed trimming hydraulic units. Gears associated with the differential and, in particular, a ring gear portion, provide rotation from the differential back into the trimming unit. A carrier also rotates another portion of the trimming unit. The trimming unit is operable to result in the output speed of the differential being effectively constant, such that electric power of a desirable frequency is generated.
The generator is mounted between two housing portions and a seal plate is mounted between the two housing portions.
In addition, various accessory systems, such as various pumps, are driven by the ring gear of the differential through an accessory drive gear.
A variable block shaft in the hydraulic unit raises design challenges.